Transcript for Woman in Critical Condition After Drinking Lye-Spiked Tea

Thank you, Ryan. Out of Utah the woman in critical condition after drinking sweet tea laced with an industrial cleaning chemical at a restaurant. This morning police investigating if it was intentional or an accident. ABC's Neal Karlinsky with the story. Reporter: 67-year-old Jan hard something fighting for her life in this Utah hospital after a simple sip of iced tea. She said, I think I just drank acid. Reporter: In a "Gma" exclusive the family is sharing the shock of something so unusual they don't quite understand it. The terror in her eyes and I looked down and said, I love you and she couldn't really even talk at that point. She just mouthed I love you too. Reporter: Police say Harding got the iced tea at this dickey's barbecue pit and it shows a heavily toxic industrial cleaner was mixed in with the ice tea in large quantities. The cleaner made up of sodium hydroxide or lye is known to cause severe burns to the mouth, throat and stomach if swallowed. It would burn the tissues in your mouth and down in your esophagus. Reporter: Police are interviewing employees and checking surveillance cameras, but say they now believe it was an accident. That the powdered cleaner may have been mixed in by an employee who mistook it for sugar. The restaurant part of a national chain said in a statement at this time we are fully involved in cooperating with all parties. We did contact the Salt Lake health department after the depth took place and said it was safe and did leave the restaurant open. If the people working in the restaurant industry could be made aware of the potential, the danger it's worth it. Reporter: For "Good morning America," Neal Karlinsky, ABC news, Los Angeles.

This transcript has been automatically generated and may not be 100% accurate.

Vermont Mom Reveals Face After Transplant

Carmen Blandin Tarleton, 44, was disfigured when her estranged husband attacked her with lye in 2007.

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